Continuously variable transmission

• US 7,077,777 B2
• Filed: 10/04/2002
• Issued: 07/18/2006
• Est. Priority Date: 10/05/2001
• Status: Expired due to Fees

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Liu, Daping, Miyata, Sinji
• Primary Examiner(s): PANG, ROGER L
• Application Number:
  US10/263,725
• Publication Number:
  US 20030069106A1
• Time in Patent Office: 1,383 Days
• Field of Search: 475/207, 475/208, 475/215, 475/216, 477/41, 477/143
• US Class Current: 475/208
• CPC Class Codes: F16H 2037/0886 with switching means, e.g. to change ranges
• CPC Class Codes: F16H 37/086 CVT using two coaxial friction members cooperating with at least one intermediate friction member
• CPC Class Codes: F16H 61/04 Smoothing ratio shift
• CPC Class Codes: F16H 61/664 Friction gearings

Abstract

A continuously variable transmission has: an input shaft, an output shaft, a toroidal type continuously variable transmission, and a planetary gear mechanism including a sun gear, a ring gear and a planetary gear. The power transmitted to first and second power transmission systems is made to converge to two gears of the planetary gear mechanism, and a remaining gear is coupled with the output shaft. A mode changeover device effects a changeover between, during forward movement, a first mode for a low speed side, which utilizes the first power transmission system and a second mode for a high speed side, which utilizes the first and second power transmission systems. Such changeover is effected by the operation of connecting and disconnecting a first mode clutch and a second mode clutch. The operation of effecting the changeover between the first mode and the second mode is effected in 0.2 to 1 second.

Claims

1. A continuously variable transmission comprising:

an input shaft rotatively driven by a drive source;

an output shaft for taking out power based on the rotation of said input shaft;

a toroidal type continuously variable transmission;

a planetary gear mechanism including;

a sun gear;

a ring gear disposed around said sun gear; and

a planetary gear provided between said sun gear and said ring gear,

wherein two transmission paths are provided for transmitting the power from said drive source to said output shaft, and

wherein the power transmitted to first and second power transmission paths is made to converge to two gears of said sun gear, said ring gear, and said planetary gear, and a remaining gear other than said two gears is coupled with said output shaft; and

a mode changeover device effecting a changeover between, during forward movement, a first mode for a low speed side and a second mode for a high speed side, the changeover between the first and second modes being effected by the operation of connecting and disconnecting a first mode clutch and a second mode clutch, wherein said mode changeover device controls varying a time over which said changeover occurs,

wherein the first mode clutch and the second mode clutch are wet clutches, and

wherein the operation of effecting the changeover between the first mode and the second mode is effected in 0.2 to 1 second.

2. The continuously variable transmission according to claim 1, wherein said two power transmission paths are said first power transmission system for transmitting the power to said planetary gear mechanism through said toroidal type continuously variable transmission and said second power transmission system for transmitting the power to said planetary gear mechanism without being routed through said toroidal type continuously variable transmission, and

wherein said first mode utilizes said first power transmission system and said second mode utilizes said first and second power transmission systems.

3. The continuously variable transmission according to claim 1, wherein said mode changeover device is a control circuit which effects the operation of connecting and disconnecting said first mode clutch and said second mode clutch in response to an output signal of said control circuit.

4. The continuously variable transmission according to claim 1, wherein said toroidal type continuously variable transmission is of a single cavity type.

5. The continuously variable transmission according to claim 1, wherein said toroidal type continuously variable transmission is of a double cavity type.